Gravel well screen



Dec. 29, 1931.. n T B MlNYARD 1,839,044

` GRAVEL WELL SCREEN Filed Jan.. 16, 1950 2 SheetsfShee l Dec. 29, 1931. T. B. MINYARD GRAVEL WELL SGREEN Filed Jan. 1e. 195o 2 Sheets-Sheet Patented Dec. 29,

ANl'rlzl) s'rxrlssl PATENT oFFicE THOMASB. MINYARD,`OF GREENWOOD, MISSISSIPPI GRAVEL WELL SCREEN Appiication med January 16, 1930. serial No. 421,23?.

This invention relates to improvements in l0 Anotherrobject of the invention is to provide an improved. well pipe screen from Lwhich sand may be readily removed by pumping water bacll through the well line 1 e. till another'object of the invention is to provide in associationwith the .screen device adapted to be attached to the lower end of a well line pipe, a resilient body which connects between the line pipe andthe wall of the well hole permitting'the washing out from the lower end of the well hole of mud but preventing mud and cavings from falling back into the bottom of the well around the screen.

The present invention. broadly. contemplates the provision of a screen consisting` of a pair of perforated pipe sections,.one being placed within and being of materially less diameter than the other, both of the pipes' being attached to the lower end of a line pipe and having. packed therebetween selected and clean gravel.

lThe invention will be best understood from a consideration of the following detailed description taken in connection with the accompanying drawings forming part of this speciiication, with the understanding,

i however, that the invention is not'conlined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes ormodifications mark no material departure from the salient features of the invention as expressed in the appended claims. f.

In the drawings 'Figure l is a longitudinal sectional view through one form'of the gravel well screen embodying the present invention, the same being shown in a Well hole.

Figure 2 is a sectional view taken upon the line 2 2 of Figure 1.

Figure 3 is a sectional view taken upon the line S of Figure 1.

Figure 4 is a modilied form of the structure shown in Figure 1, this form being for use in small diameter bores.

Figure 5 is a further modified form of the structure shown in Figure l, this modified forni being for very large'wells and so designed as to prevent sticking in the mud and sand therein.

Referring more particular-ly to the drawings wherein like numerals of reference indicate. corresponding parts throughout a the several Views, the numerals 1, 2 and 3 indicate respectively strata of shale, sand and hard packed earth such as is frequently encountered in the bottom of a well, the fluid to be moved iiowing into the well 'hole from the .sand stratum. The function of the present screen device is to prevent the sand from` this stratum entering the well line pipe.

In Figure 1 the w-ell line pipe-is indicated by the numeral 4. The' gravel screen structure constituting the present invention is shown attached to the lower end of the line pipe 4 and is indicated as a whole by the nu- 'meral 5. As shown this screen consists of an inner tube or pipe 6 and an outer pipe 7 which pipes should properly be of brass or bronze but may be of the same material as the line pipe. Both of these tubes 6 and 7 are provided throughout with.apertures either in the form of circular openings or in the form of longitudinally extending slots, 'these openings being indicated in both tubes by the numerals 8. i p l i The inner tube 6 is connected with the lower section ofthe line pipe 4, which section iseX- bushing being maintained in place by and between the collars 10 and 14, the collar 14 being threaded onto the line pipe 4 and located above the collar 10 and the bushing as shown.

The bushing 13 is exterior-ly threaded and is threaded into a collar 15, this collar also receiving the exteriorly threaded upper end of the outer tube 7.

At its lower lend the inner tube 6 has coupled thereto by means of a collar 16, a nipple 17 between which and the tube 6 a centrally apertured plate 18 is secured through which the lower end of the wash pipe 12 passes as shown. rI`he lower end of this nipple 17 has connected therewith bv means of a second collar such as is indicated at 19, a second nipple 20 between which and the nipple 17 a centrally apertured valve plate 21 is secured against the lower side of which a downwardly opening spring pressed valve 22 is held.

The lower nipple 20 is exteriorly threaded to receive a lower bushing 23, which bushing is exteriorly threadedas is also the adjacent end of the outer tube 7 to receive with the outer tube a set shoe 24 which as shown is in the form of a broad annular body the lower edge of which is sharpened as indicated at 25 so as to cut into the hard pan 3 in the bottom of the well. Before closing one end of the double walled body 5 there is placed between the tubesconstituting the walls thereof clean, selected gravel 26, the space between these tubes being completely filled as shown. Disposedbetween the tubes 6 and 7 are spacing or guide spiders 27 which serve to prevent deformation of the tubes 6 and 7 which make up the inner and outer walls of the screen.

In order to prevent soft mud and other undesirable matter from getting down intothe lower part of the well bore between the screen structure 5` andthe sand stratum there is secured to the upper bushing 13 and about the line pipe 4 a heavy flexible ring 28 which is preferably formed of rubber, suitable screws or bolts 29 serving to secure the inner portion of this ring to the top of the bushing 13 in the manner shown.

While I have shown only a single length of tubing for the inner and outer walls of the gravel screen structure it is of course to be understood that any number of lengths of this tubing may be employed to increase or decrease the length of the gravel screen as desired.

When a well pipe equipped with the gravel screen embodying the present invention is being placed'in position in a well bore compressed air may be forced down through the wash pipe 12 or through the line pipe as desired to force the sand in the bore out of the way to permit the screen to take up its proper position therein and as the screen is lowered the flexible ring 28 which acts in the nature of a valve will permit mud and water to pass up around the line pipe. After the screen has been set in the bottom of the well water may be forced down through the wash pipe for discharge down through the valve 22 and out into the area surrounding the screen 5 washing out the screen and forcing mud up past the valve 28 so that only clean sand may be left in the lower part of the well. When all ofthe mud has been washed from around .V the outside of the screen and the pumps forcing the water through the wash pipe 12 have been stopped the flexible vring or valve 28 will engage the wall of the well hole and prevent cavings and mud from above the sand stratum falling back around the gravel screen. i

From the foregoing it will be seen that, after the well pipe and screen have been set in the manner described only clean sand will surround the screen 5 and as suction is ap plied to the line pipe water, oil or whatever substance is being removed from the well will be sucked through the gravel screen to be drawn up through the line pipe free of sand and other matter.

In Figure 4 a slightly modified form of the structure shown in Figure 2 is illustrated. In this form the over-all diameter of the gravel screen structure which is here indicated as a whole by the numeral 30 is the same as the line pipe 31, the outer tube 32 of this form of the invention being coupled to the line pipe by a collar 33 between which and the adjacent end of the line pipe a bushing 34 is held, the inner tube 35 which is of materially smaller diameter than the line pipe being threadably secured at its upper end in the bushing 34 in the manner shown. The fieXible member or valve 36 which surrounds the lower end of the line pipe is here secured directly to lthis pipe. The elements making up the lower part of this modified form of screen are the same and are coupled together in exactly the same way as those in the screen shown in Figure 1 and indicated generally by the-numeral 5, these elemems being indicated by numerals corresponding to those in Figure 1 eachr of which is, however,` distinguished from the numerals in Figure 1 by an a.

In Figure 5 a still further modification of the structure shown in Figure 1 is illustrated, this modified form of the screen being designed for use in relatively large wells where a greater amount of screening material is necessary and where the possibilities of the screen becoming stuck are greater. In this form of screen the line pipe which is here indicated by the numerall 37 has a substantial 325 portion of its lower end perforated as indicated at 38 and at the upper and lower ends of this perforated area it is provided with the screw threads 39 and 40. This perforated flower area of the line pipe constitutes the lil inner portion of the screen structure which here indicated vgenerally by the numeral The outer perforated tube 42v of this form is of slightly greater diameter at its lower end than at its upper end and is interiorly threaded at its upper end as shown to receive a bushing 43 through which the line pipe 37 passes. The perforated lower portion of the Aline pipe 37 is formed separate from the up- Threaded upon the lower end of the line pipe 37 isa lower bushing 47 which is'eX- teriorly threaded for@ engagement with threads formed in the interior wall of a set shoe 48,l this set shoe receiving the lower end of the outer cylinder 42 and being secured thereto by suitable bolts or rivets 49.

From the foregoing -it will be readily seen that the tapered screen is so designed that the outer -surface will be smooth throughout,- particularly atgthe upper end so that it may be made to easily penetrate the sand and mud in the lower part of a well, it, of course, being understood that while the yscreen is being placed in positon 'air will be pumped into the well so as to force sandfrom beneath the e screen and up around the side's'to make suflicient room inthe bottom of the well for the screen to enter. By making this form of screen tapered as shown it will notl stick in the sand like a straight screen might do if placed in a large well. The rubber mud retaining ring or valve -45 of course operates in the same way in connection with this form of the screen .as described in connection with the forms shown in-Figures l andI 4.

After the tapered screen has been .set the Vlower end of the pipe line 37 may be closed by cement or any other suitable material introduced thereinto and allo-wed to settle in the lower end thereof.

From the foregoing description it will be readily seen that a screen constructed inaccordance with the present inventionv will have a much longer useful life than the usualV all metal screens employed at the present time and in additionto this it is believed to be readily obvious that the present improved screen maybe readily washed out-inthe event that sufficient sand penetrates the interstices between the gravel to interfere with the operation of the screernby reversin the flow ofl water through the line pipe to orce it down and outthrough the screen into the well, this excess water entering the well being forced up past the valve surrounding the lower end of the line pipe thus cleaning out the well at the same time that it cleans the screen.

Having thus described my invention, what I claim is I f v l. A well screen, comprising a pair of perforated tubular bodies, one within and spaced from the other, means for coupling one of said bodies with a well line pipe, consisting of a threaded collar designed to span adjacent -ends of the said one of the bodies and the pipe, an imperforate annular body designed to surround the well pipe, means for coupling said annular body with the upper end of the other perforated body, a flexible cup washer surrounding thewell pipe and resting upon the annular body, means for securing. the washer to the. annular body, an

imperforate annular body surrounding the lower end of the inner one ofsaid perforated bodies and bea-ring against the Vadjacent'end ofthe other perforated body, granular matter filling the area between said perforated bodies, and a set shoe surrounding the lower end of the outer perforated body and having threaded connection with the adjacent annular body.

2. A- well screen for well line pipes, comprising a pair of perforated tubular bodies, one within the other, a collar having threaded connection with the upper end of the inner body and coupling the same with the well line pipe, an imperforate annular member suroundingthe well line pipe above and engagingsaid collar, means for threadably coupling the upper end of the outer body with said' annular member, a. cup washer sur-4` rounding the pipe and restinguponv and secured to the annular member, an imperforate annular body y threaded connection'with the lower end of the inner perforated body, a set shoe surrounding and secured to the lower end of the outer perforated bodv and having threaded connection with said annular body, granular matter filling thespace between said perforated bodies, said inner body being divided adjacent its lower end, an apertured plate within the inner body and secured'between the adjacent ends of; the portions formed by dividing the same, and a downwardly opening valve controlling the aperture of said plate.

3. Av screen for well line pipes, comprising a pair of perforated tubular bodies, one of less diameter than and within the other, an imperforate annular body Vsurrounding and having threaded connection with the upper end .of the inner one of said bodies and bearing against the upper end ofthe outer body, said annular body having a well pipe bearing thereagainst, a collar surrounding said well pipe, annular body and outer perforated-body and securing the three together,

surrounding and having t a cup washer surrounding the well pipe and secured thereto above said collar, an imperforate annular member surrounding and having threaded connection with the ower end of the inner perforated body and bearing against the lower end of the outer perforated body, and a set shoe surrounding the last mentioned annular member and the lower end of ,the outer body and having threaded connection therewith to hold the same in position.

4. A screen for well line pipes, comprising a pair of perforated tubular bodies, one within and of less diameter than the other, a collar surrounding the upper end of one of said bodies and coupling the same with a well pipe, a cup washer surrounding the well pipe adjacent the upper ends of the perforated bodies, means for closing'the space between the perforated bodies at the lower ends there'- of, a set shoe rmounted upon the lower end of the outer body, said inner apertured body being formed to provide a pair of removable sections at its lower end, a pair of centrally apertured plates, one being interposed between one removable section and the adjacent end of the body, the other plate being interposed between the two sections, a wash water pipe extending longitudinally through the inner body and passing through the first mentioned apertured plate, and a downwardly opening valve controlling the aperture of the last mentioned one of said plates.

5. A screen for well line pipes, comprising a pair of perforated tubular bodies disposed one within the other, connecting means between said bodies at one end, means for attaching the bodies at the connected ends to al well line pipe, the inner one of said perforated bodies being exteriorly threaded at its lower end, a set shoe encircling the lower end of the outer perforated body and having screw threads formed upon its interior surface, a flat annular body having both interiorand exterior threads and receiving the threaded lower end of the inner perforated body and having threaded connection between its eX- terior threads and the threads within said outer body at its upper end, a set shoe surrounding the lower end of the outer perforated body, a flat annular body threadably engaging the lower end of the inner perforated body and having threaded connection with said shoe and bearing against the lower end of the outer body, granular material filling the area between the perforated bodies, a flexible cup washer adapted to circle the well pipe and resting upon the top of the first mentioned annular body, and means for securing the cup washer to the said first mentioned annular body.

In testimony whereof, I hereunto aflix my signature.

THOMAS B. MIN YA RD.

shoe, the lower end of said exterior perforated body being in abutting relation to theA annular body,.granular material lling the area between the perforated bodies, and a flexible washer surrounding the well nine and disposed above the perforated bodies.

6. A screen for well line pipes, comprising a pair of perforated tubular bodies one disposed within the other, the inner one of the bodies being threaded upon its upper and lower ends, a collar threaded about the upper end of the inner body and adapted to couple the lower end of a well pipe thereto, a flat annular body adapted to surround the lower end of the well pipe and to rest upon said collar and further having threads about its outer edge for engagement with the interior of the 

